A typical prior art hole cutter includes a cylindrical blade body defining a plurality of saw teeth on the cutting edge of the blade body, and one or more apertures formed through an intermediate portion of the blade body. Typically, smaller diameter hole cutters have fewer apertures formed through the blade bodies, and larger diameter hole cutters have more apertures formed through the blade bodies. The apertures formed through prior art hole cutter blade bodies may define a variety of different configurations to facilitate inserting a tool into the apertures, such as a screw driver, to remove circular work piece slugs from the interiors of the blade bodies.
One of the drawbacks encountered with prior art hole cutters is that chips or dust, particularly when cutting wood, collects within the interiors of the hole cutters between the work piece slugs and the caps on the non-working ends of the hole cutters. The apertures formed in the side walls of the blade bodies are designed to allow the insertion of screw drivers or like tools to remove work piece slugs, but are not configured to allow the chips or dust generated during cutting to flow through the apertures and away from the interiors of the blade bodies. The chips and dust that collect within the interiors of the blade bodies can become compacted and rapidly fill the hole cutters. Chips and dust also collect at the interfaces between the blade bodies and work pieces, such as between the external surfaces of the blade bodies and the work pieces. The chips and dust that collect at the interfaces of the blades bodies and work pieces can become heated due to frictional forces created between the rotating blade bodies, collected chips and dust, and work pieces. The thermal energy created by such frictional forces can be sufficient to cause the paints or coatings on the external surfaces of the blade bodies to become soft or gooey. The collection of chips and dust within the interiors of the blade bodies and/or at the interfaces of the blade bodies and work pieces can significantly reduce the cutting efficiency and overall cutting speed and/or blade life of such hole cutters.
Although many prior art hole cutters include one or more apertures formed through the side walls of the blade bodies, the apertures are not configured to facilitate the flow of chips from the interiors of the blade bodies into and/or through the apertures. In some such hole cutters, the apertures are spaced too far from the cutting edge, such that the chips generated at the cutting edge become packed between the interior of the blade body and the work piece slug prior to reaching the aperture(s). In other such hole cutters, the apertures are too small to allow any material volume of chips to flow into the apertures and/or through the apertures such that the apertures do not materially impact chip egress. In other such hole cutters, the apertures are not configured to cause the chips to flow into or through the apertures and away from the cutting edge and interiors of the blade bodies.
Accordingly, it is an object of the present invention to overcome one or more of the above-described drawbacks and/or disadvantages of the prior art.